logo-loader

Mining 101: An A-Z guide of mining terms

Last updated: 09:30 28 Sep 2021 AEST, First published: 08:24 28 Sep 2021 AEST

Mining terminology is tricky to understand. And to be frank, most investors wouldn’t know a blebby from a ball mill. With that in mind, we’re here to help you navigate the greenfields, brownfields and mine fields of mining speak.

For investors with a non-mining background, deciphering ‘geospeak’ — the phrases and terminology only geologists know – can be a confusing and oftentimes onerous task.

Put simply, mining terminology is tricky to understand. And to be frank, most investors wouldn’t know a blebby from a ball mill.

With that in mind, we’re here to help you navigate the greenfields, brownfields and mine fields of mining speak.

Following is an A-Z guide of mining terms.

We hope this helps you with your investment decisions and your basic understanding of how the mining industry operates.

AC drilling: Aircore drilling. An air blast drilling technique that utilises high-pressure air and dual walled rods to penetrate the ground. AC drilling enables miners to return samples to the surface, however, it has limited coring capability.

Alluvial deposit: Clay, silt or gravel carried by rushing streams and deposited where the stream slows down.

Anomaly: A zone different from its surroundings – usually determined by exploration methods.

Assay: Compositional analysis of an oremetal, or alloy

Ball mill: Device used to reduce broken ore into powder (grinding). 

Banded Iron Formation (BIF): Iron formation consisting of alternate silica-rich and iron-rich layers.

Bankable feasibility study (BFS): A BFS represents a base case for financiers and when positive provides all the information necessary for a bank to determine the viability of a project.

Base metals: Common non-precious metals including lead, copper, zinc and nickel.

Beneficiation: A process where the grade of the mined ore is increased by removing high impurities. It can be done via classification, gravity, wet or dry magnetic separation or flotation processes. Beneficiation usually takes place in a beneficiation plant.

Blast furnace: A reaction vessel. Mixed charges of oxide ores, fluxes and fuels are blown with a continuous blast of hot air and oxygen-enriched air for the chemical reduction of metals to their metallic state.

Blebby: Possibly the worst word in mining. Something that has small bubbles or imperfections.

Brownfields: Exploration at or within close proximity to known ore deposits.

Bulk sample: A large sample of mineralised rock that is representative of the potential orebody being sampled. Used to determine metallurgical characteristics.

Bullion: Gold or silver in bars or ingots. 

Carbon in leach (CIL) process: A recovery process. A slurry of gold ore, carbon granules and cyanide are mixed. The cyanide dissolves the gold content and the gold is absorbed on the carbon; the carbon is subsequently separated from the slurry for further gold removal.

Carbon in pulp (CIP) process: Like the carbon-in-leach process, however, the slurry is first subjected to cyanide leaching in separate tanks followed by carbon-in-pulp. Carbon-in-leach is a simultaneous process.

Coke (in reference to coal): Solid residue remaining after certain types of coals are heated to a high temperature. 

Coking coal (metallurgical coal): A grade of coal that meets the requirements for making coke. It must have a low ash and sulphur content and form a coke that can support the charge of iron ore and limestone in a blast furnace.

Cut-off grade: A grade level below which the material is not 'ore' and considered to be uneconomical to mine and process. 

Definitive feasibility study (DFS): The most detailed form of feasibility study which determines definitively whether to proceed with a project. 

Diamond drilling: Rotary drilling using diamond set or diamond impregnated bits, to produce a solid continuous core sample.

Down dip: Down and along a dip.

Drilling permit: Permission to drill at a specified location. 

Drilling: Speaks for itself. Boring a hole into ground, usually to recover core (cuttings) indicative of rock types and grades of mineralisation. 

DSO (Direct shipping ore): High-grade hematite is often referred to as DSO. It is mined and beneficiated using a crushing and screening process before being exported without further treatment for use in steel mills. 

Enterprise value (EV – not electric vehicle related): Market cap plus debt, minority interest and preferred shares, minus total cash and cash equivalents.

Environmental impact study (EIS): A report examining the effects proposed mining activities will have on the environment.

Epithermal deposit: A mineral, or type of lode deposit, consisting of veins and replacement bodies, usually in volcanic or sedimentary rocks, containing precious metals including gold. 

EPS (Earnings per share): The portion of a company's profit allocated to each share.

EV/Resource ounce (oz): A valuation method, usually referring to the amount paid in dollars per ounce of resource. 

Farm in: Common in the Australian exploration sector, a Farm-in Agreement is an agreement where the owner of an interest in a lease or licence grants the right to acquire a percentage of their interest to a second party for the purpose of exploration contingent upon that party spending funds on the exploration.

Fault: a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures as a result of earth movement.

Feasibility study: An evaluation of a proposed mining project to determine whether the mineral resource can be mined economically. There are four types of feasibility studies used in mining: scoping, preliminary feasibility (PFS), definitive feasibility (DFS) and bankable feasibility (BFS).

Geothermal: referring to the heat of the earth’s interior.

Hanging wall: The rock on the upper side of a vein or ore deposit.

Head grade: The average grade of ore delivered to the mill. 

Indicated resource: That part of a mineral resource for which tonnage, grade and mineral content can be estimated with a reasonable level of confidence.

Inferred resource: Part of a mineral resource for which tonnage, grade and mineral content can be estimated with a low level of confidence.

JORC code: Australasian professional code of practice that sets minimum standards for public reporting of minerals exploration results including mineral resources and ore reserves. The JORC Code is produced by the Australasian Joint Ore Reserves Committee.

Joint venture (JV): A business arrangement in which two or more parties agree to pool their resources for the purpose of accomplishing a specific task.

Magnetic separation: A process in which a magnetically susceptible mineral is separated from waste by applying a strong magnetic field; ores of iron are commonly treated in this way.

Magnetic survey: Technique that measures variations in the earth’s magnetic field. This defines the distribution of values that may be indicative of different rock types.

Mill: A plant where ore is ground fine and undergoes physical or chemical treatment to extract the valuable metals.

Mill feed grade: The grade of material fed at the mill.

Mineralised zone: An enriched zone of mineral deposits.

Net smelter returns: the value received for a mineral after refining, less the cost of transporting the mineral to the refinery and the cost of refining. 

NPV: Net present value: the sum of discounted positive and negative cashflows.

Open in all directions: Drilling has encountered mineralisation along strike and at depth as far as the drilling has been conducted

Open pit: An on surface mine.

Probable reserve: Can be mined in an economically viable fashion. Sufficient quality to be a basis for decision on further deposit development. 

Proven reserve: Can be mined in an economically viable fashion. A proven ore reserve represents the highest confidence category of reserve estimate.

RC (reverse circulation) drilling: More effective than RAB and aircore drilling. Drill cuttings are returned to surface inside the rods. RC drilling is slower and costlier but achieves better and deeper penetration. 

Recovery: A term used in process metallurgy to indicate the proportion of valuable material obtained in the processing of an ore. 

Refining: Extracting and purifying metals and minerals. 

Reserves: Are valuable, and legally, economically and technically feasible to extract. Reserves can be classified as proven or probable for miners. For oil and gas companies, reserves are proven, probable or possible.

Rock chip sampling: Collection of rock samples by breaking chips off a rock face for chemical analysis.

Rotary Air Blast (RAB) drilling: Also known as down-the-hole drilling, this common shallow method employs a pneumatic hammer with tungsten 'teeth' that chew away the rock surface as debris is blown up and out through the excess space surrounding the rod.

Scoping study: Initial financial appraisal of an indicated mineral resource.

Seismic survey: Exploration method in which strong low-frequency sound waves are generated on the surface or in the water to find subsurface rock structures that may contain hydrocarbons. 3-D Seismic means seismic data that is acquired and processed to yield a three-dimensional picture of the subsurface.

Shear zone: A zone of closely spaced, approximately parallel faults or dispersed displacements.

Strike: Direction of the line formed by the intersection of a fault, bed or other planar feature and a horizontal plane.

Strike length: Distance along strike.

Strip ratio: The ratio of tonnes removed as waste relative to the number of tonnes of ore removed from an open-pit mine. 

Sulphide ore: Sulphide ores are generally found hundreds of metres below surface and generally require underground mining infrastructure. The main benefit to sulphide ores is that they can be concentrated using a simple physical separation technique called flotation.

Tailings: The material that remains after all metals considered economic have been removed from ore during milling.

Tailings dam: Structure that holds back the storage of tailings

Tenement: Ultimate result of an area selection process. A permit, claim, licence or lease that may be granted.

Vein: A fissure, fault or crack in a rock filled by minerals that have travelled upwards from some deep source.

Volcanogenic massive sulphide (VMS): A type of metal sulphide ore deposit, mainly copper-zinc-lead, associated with and created by volcanic-associated hydrothermal events in submarine environments.

Working interest: A working interest in an oil or gas property is one that is burdened with the cost of development and operation of the property, such as the responsibility to share expenses of drilling. 

Australian Strategic Materials signs US$600 million LoI

Rowena Smith, CEO and managing director of Australian Strategic Materials Ltd (ASX:ASM, OTC:ASMMF), joins Jonathan Jackson in the Proactive studio to discuss the company’ s Dubbo Project, in Central West New South Wales. This project aims to extract and process critical minerals and rare earth...

11 hours, 59 minutes ago